1. Field
The present invention relates to static control garments and monitoring devices.
In particular, the present invention relates to a monitoring device for use with an insulated dual portion garment.
2. Description of the Related Art
Static electricity represents a serious threat to electronic components, which may become damaged during the manufacturing process when the personnel handling these components are not effectively grounded. It is desirable to ground not only the bodies of the personnel working with these components, but their clothing as well, as charge can build up in either location.
The “bunny suit” is a popular garment used to ground personnel and their clothing. Typically, the bunny suit is made from a knit or woven fabric comprising an electrically conductive Faraday cage grid. The garment thereby effectively shields the personnel and his or her clothing from delicate electronic components. One or more close fitting connections may also be used to electrically couple the wearer's body to the bunny suit and/or to ground. For example, a wrist strap having an attached grounding cord may be incorporated into the bunny suit in order to couple the wearer's body to ground.
Unfortunately, the conventional bunny suit is not ideal. For example, in order to determine whether or not the bunny suit is effectively grounding its wearer, two connections should couple the wearer to a monitoring circuit. However, because the entire garment is made from electrically conductive material, a number of uncontrolled parallel electrical paths are formed between the wearer's body, street clothing and bunny suit, and the monitoring circuit. These parallel paths can make the monitoring circuit's output unreliable.
Moreover, the grounding of the bunny suit is typically only tested occasionally. The use of conventional monitoring circuits is inconvenient (often requiring the wearer to manually touch a ground, for example, to define a current loop), and they may be located far from where the wearer is working with the electronic components.
The prior art has not disclosed an effective way of monitoring the status of a wearer's connection to ground. The prior art has also not disclosed an effective way to ameliorate the problem of multiple, uncontrolled parallel electrical paths undermining the accuracy of ground monitoring.